Optical module and lead frame for optical module

ABSTRACT

An optical module, including a plurality of optical devices and a plurality of circuit devices, which is suitable for a smaller size and a higher density, and a lead frame for the optical module are provided. The optical module comprises optical devices, circuit devices 30, 32 electrically connected to the optical devices; a lead frame mounting these devices on the same main surface; and a first encapsulating resin body 66, transparent to light processed by the optical devices, for encapsulating the optical devices. The lead frame has a single first die pad for mounting a plurality of optical devices; a plurality of second die pads 4, 6 each for mounting a circuit device; connection lead groups 40, 42, whose number is the same as that of the second die pads, having a plurality of connection leads 44, 48 for electrically connecting the optical devices mounted on the first die pad to the circuit devices mounted on the second die pads 4, 6; and wiring leads 50, 51 arranged so as to face the respective side faces of the second die pads 4, 6. In the optical module, the optical devices are connected to the wiring leads 50, 51 by way of the connection leads 44, 48.

TECHNICAL FIELD

The present invention relates to an optical module and a lead frame forthe optical module; and, in particular, to an optical module mounting aplurality of optical devices and a plurality of semiconductor circuitdevices on the same lead frame, and the lead frame for the opticalmodule.

BACKGROUND ART

Attempts have conventionally been made to attain the higher packingdensity of parts using a lead frame. As an example of such attempts,there is a technique disclosed in Japanese Patent Application Laid-OpenNo.1-257361. FIG. 15 is a sectional view of the semiconductor assemblydisclosed in the above-mentioned publication. Referring to FIG. 15,semiconductor elements 404, 404' are mounted on the surfaces of two leadframes 401, 401', respectively. Electrode pads on the individualsemiconductor elements 404, 404' are connected to their correspondinginner leads by bonding wires 403, 403', respectively. Then, with theirrear faces faced to each other, the two lead frames 401, 401' areoverlaid on each other with an insulating film 405 interposedtherebetween. Subsequently, the semiconductor elements 404, 404' areencapsulated with an encapsulating resin body 402. Thereafter, the outerlead pins of the two lead frames are bent in one direction. Since theouter lead pins of the two respective lead frames are bent with theirdifferent lengths, they would not come into contact with each other.

DISCLOSURE OF INVENTION

In the semiconductor assembly having such a configuration, an electricconnection between the two lead frames is made via an outer lead.Additional outer lead pins are required for connecting the respectivesemiconductor elements mounted on the different lead frames to eachother, whereby the number of the outer lead pins cannot be reduced evenwhen this configuration is employed. It cannot improve the packingdensity of the semiconductor assembly.

If such a configuration is applied to an optical module such that atransmitting unit and a receiving unit are mounted on the two leadframes, respectively, and are integrally encapsulated with resin, thenthe signal light emitting and receiving faces of the transmitting andreceiving units are located back to back, whereby their opticalcouplings cannot be made in the same direction.

On the other hand, in a module in which a light-receiving element orlight-emitting element and a circuit element are mounted to a singlelead frame, the light-receiving element and a preamplifier have beenseparately encapsulated with resin to make a light-receiving module, orthe light-emitting element and its driver IC have been separatelyencapsulated with resin to make a light-emitting module. In order tomake a transmitter/receiver module, it is necessary to assemble a modulefor a receiving portion and a module for a transmitting portion, so asto produce the transmitter/receiver module. As the distance between thelight-emitting element and the light-receiving element becomes shorter,the circuit element portion must be made smaller depending on thisdistance, whereby it is hard to secure an area for mounting the circuitelements.

When a main amplifier, a clock data reproducing circuit, and the like,in addition to the preamplifier, are mounted to the circuit elementmounting portion, the mounting area for such additional circuit devicescannot be secured.

Therefore, it is an object of the present invention to provide anoptical module, having a plurality of optical semiconductor devices anda plurality of circuit devices with their emitting and receiving facesfaced to one direction, which is suitable for a smaller size and ahigher density; and a lead frame for the optical module.

The present invention is configured as follows.

The optical module in accordance with the present invention comprises anoptical device which is one of a semiconductor light-receiving deviceand a semiconductor light-emitting device, a semiconductor circuitdevice, a lead frame, and a first encapsulating resin body. Thesemiconductor light-receiving device is provided for receiving anoptical signal, converting thus received optical signal into an electricsignal, and outputting thus obtained electric signal. The semiconductorlightemitting device is provided for receiving an electric signal,converting thus received electric signal into an optical signal, andemitting thus obtained optical signal. The semiconductor circuit device,electrically connected to the optical device, is provided for processingthe electric signal. The lead frame is provided for mounting the opticaldevices and the semiconductor circuit device on a surface thereof. Thefirst encapsulating resin body, transparent to signal light processed bythe optical device, encapsulates the optical devices. The lead frame hasa single first die pad for mounting a plurality of optical devicesthereon; a plurality of second die pads for mounting the semiconductorcircuit devices thereon; connection lead groups; and a wiring leadarranged so as to face a side of the second die pad. The number of theconnection lead groups is identical to that of the second die pads. Eachof the connection lead groups have a plurality of connection leads, andhas one end arranged so as to face one side of the first die pad and theother end arranged so as to face one side of the second die pad. Theconnection lead groups electrically connect the optical devices mountedon the first die pad to the semiconductor circuit devices mounted on thesecond die pads. The optical devices can be electrically connected to awiring lead by way of a connection lead.

The plurality of optical devices are mounted on the single first diepad, whereby the distance between the optical devices can be reduced,and the emitting face and receiving face for the optical signal can befaced to the same direction. The optical module having aresin-encapsulated optical device portion can be provided. Since thelead frame mounted with the optical devices is provided with a pluralityof second die pads on which the respective circuit devices are mounted,an area for mounting a plurality of circuit devices can be secured.Further, the optical devices mounted on the first die pad can bedirectly and electrically connected to the circuit devices mounted onthe second die pads by connection lead groups. The number of theconnection lead groups is identical to that of the second die pads. Eachof the connection lead group comprises a plurality of connection leads,and has one end provided so as to face one side of the first die pad andthe other end provided so as to face one side of the second die pad.Consequently, the number of wiring leads can be reduced.

The optical module in accordance with the present invention can beconfigured such that the lead frame has two second die pads, and therespective connection lead groups are provided so as to face a pair oftwo opposite sides of the first die pad, and each connection lead grouphas a bent portion at a predetermined position at which it is bentsubstantially at right angles so that the respective rear faces oppositeto the mounting surfaces of the second die pads are oriented to face toeach other.

As each connection lead is thus bent at a predetermined position so thatthe rear faces are faced to each other, i.e., inward, thetwo-dimensional size of the optical module can be reduced.

In the optical module in accordance with the present invention, thefirst encapsulating resin body can have light collecting means providedon the optical axis of the signal light associated the optical devices.

When the encapsulating resin body thus has the light-collecting means onthe optical axes of the signal light, it is not necessary to provide theexternal light-collecting means and the optical module can be alsoprovided with the optical devices and the light-collecting means alignedto each other.

The optical module in accordance with the present invention can furthercomprise a second encapsulating resin body for integrally encapsulatingthe semiconductor circuit devices mounted on the respective second diepads.

When the circuit devices are thus integrally encapsulated with anencapsulating resin, then an optical module reduced in its size can beprovided.

The optical module in accordance with the present invention can furthercomprise second encapsulating resin bodies for separately encapsulatingtwo semiconductor circuit devices mounted on the respective second diepads.

When the circuit devices are thus separately encapsulated withencapsulating resins, the flexibilty in the arrangement of the circuitdevices within a light-emitting module can be enhanced.

In the optical module in accordance with the present invention, theoptical devices can be provided on the first die pad such that theoptical axes of the optical devices is conformed to the core interval ofadjacent optical fibers in a ribbon fiber cable.

When the optical axes of the optical devices thus is conformed to thecore interval of adjacent optical fibers in the ribbon fiber cable, theportion required for being connected with the fiber cable can be madesmaller.

The lead frame for an optical module in accordance with the presentinvention is provided so as to mount a semiconductor circuit device andan optical device thereon which is at least one of a semiconductorlight-receiving device and a semiconductor light-emitting device. Thesemiconductor light-receiving device receives an optical signal,converts thus received optical signal into an electric signal, andoutputs thus obtained electric signal. The semiconductor light-emittingdevice receives an electric signal, converts thus received electricsignal into an optical signal, and emits thus obtained optical signal.The semiconductor circuit device, electrically connected to the opticaldevice, processes the electric signal. The lead frame comprises a singlefirst die pad; a plurality of second die pads; connection lead groups;and a plurality wiring leads. The single first die pad is provided so asto mount the optical device. The plurality of second die pads areprovided so as to mounting the semiconductor circuit devices. The numberof the connection lead groups is identical to that of the second diepads. Each connection lead group has a plurality of connection leads.The connection lead group has one end arranged so as to face one side ofthe first die pad and the other end arranged so as to face one side ofthe second die pad. The connection lead groups electrically connect theoptical devices mounted on the first die pad to the semiconductorcircuit devices mounted on the second die pads. The plurality of wiringleads face a side of the second die pad and are arranged so as toelectrically connect the semiconductor circuit devices and the opticaldevices to outside.

The first single die pad which can mount a plurality of optical devicesis provided, whereby the reduced arrangement of the optical devices tobe mounted thereon can be attained, and it is possible to provide a leadframe in which the optical signal emitting and receiving faces of theoptical devices can face to the same direction. Since the lead framemounted with the optical devices is provided with a plurality of seconddie pads which can be mounted with the circuit devices, it is possibleto provide a lead frame which can secure an area for mounting aplurality of circuit devices. Further, the lead frame is provided withconnection lead groups, the number of which is identical to that of thesecond die pads. Each of the connection lead groups comprises aplurality of connection leads. Each of the connection lead groups haveone end arranged so as to face one side of the first die pad and theother end arranged so as to face one side of the second die pad.Therefore, it is possible to provide a lead frame in which the opticaldevices mounted on the first die pad can be directly and electricallyconnected to the circuit devices mounted on the second die pads.Consequently, the number of wiring leads can be reduced.

The lead frame in accordance with the present invention can beconfigured such that two second die pads are provided, the respectiveconnection lead groups have portions to be bent substantially at rightangle and are arranged so as to face a pair of two opposite sides of thefirst die pad, and the second die pads face respective plains containingthe two sides of the first die pad and are arranged on an axis while thefirst die pad is sandwiched therebetween.

In such a lead frame, each connection lead can be bent at apredetermined position substantially at the right angle, so that therespective rear faces opposite to the mounting surfaces of the twosecond die pads are oriented to face each other, i.e., inward. As aconsequence, it is possible to provide a smaller optical module leadframe in two-dimensional size.

The lead frame in accordance with the present invention can beconfigured such that each second die pad is provided with a referenceaxis extending through both one side of the second die pad facing theconnection lead group and the opposite side paired therewith, and thewiring leads are arranged so as to be extended to left and right sidesof the reference axis. Also, it can be configured such that each seconddie pad is provided with a reference axis extending through both oneside of the second die pad facing the connection lead group and theopposite side paired therewith, the wiring leads are arranged so as toface one second die pad in the left and right sides of the referenceaxis, and the wiring leads are arranged so as to face the other seconddie pad in the side face of the left and right sides of the referenceaxis. Further, the wiring leads can be arranged so as to face the sidesof the second die pads opposite to the sides thereof on which the seconddie pads face the first die pad.

Thus, drawing the wiring leads in predetermined directions can providean optical module lead frame which is suitable for high-densitypackaging and appropriate for connecting with an optical waveguide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a principal portion of the optical module leadframe in accordance with a first embodiment;

FIG. 2 is a perspective view of a die capacitor mounted with opticaldevices;

FIG. 3 is a perspective view of a sub-mount mounted with opticaldevices;

FIG. 4A is a perspective view of an optical module encapsulated with amolding resin, whereas

FIG. 4B is a sectional view taken along the section I-I' indicated inFIG. 4A;

FIG. 5A is a perspective view of an optical module encapsulated with anencapsulating resin, whereas

FIG. 5B is a sectional view taken along the section II-II' indicated inFIG. 5A;

FIGS. 6A and 6B are sectional views of optical device portions forlight-collecting means, whereas

FIG. 6C is a sectional view of a two-firament optical fiber cable;

FIG. 7 is a plan view of a major portion of the optical module leadframe in accordance with a second embodiment;

FIG. 8A is a perspective view of an optical module encapsulated with amolding resin, whereas

FIG. 8B is a sectional view taken along the section III-III' indicatedin FIG. 8A;

FIG. 9A is a perspective view of an optical module encapsulated with amolding resin, whereas

FIG. 9B is a sectional view taken along the section IV-IV' indicated inFIG. 9A;

FIG. 10 is a plan view of a major portion of the optical module leadframe in accordance with a third embodiment;

FIG. 11A is a perspective view of an optical module encapsulated with amolding resin, whereas

FIG. 11B is a sectional view taken along the section V-V' indicated inFIG. 11A;

FIG. 12A is a perspective view of an optical module encapsulated with amolding resin, whereas

FIG. 12B is a sectional view taken along the section VI-VI' indicated inFIG. 12A;

FIG. 13 is a plan view of a major portion of the optical module leadframe in accordance with a fourth embodiment;

FIG. 14A is a top plan view of an optical module encapsulated with amolding resin,

FIG. 14B is a bottom view of the optical module,

FIG. 14C is a front view of the optical module, and

FIG. 14D is a sectional view taken along the section VII-VII' indicatedin FIG. 14A; and

FIG. 15 is a sectional view of a semiconductor assembly in the priorart.

BEST MODES FOR CARRYING OUT THE INVENTION

In the following, the present invention will be explained with referenceto the accompanying drawings. Parts identical to each other will bereferred to with identical numerals if possible, without repeating theiroverlapping explanations.

(First Embodiment)

FIG. 1 is a plan view of a main portion of the lead frame in accordancewith the first embodiment. Referring to FIG. 1, the lead frame 1comprises a planar first die pad 2, made of electric conductivematerial, located at the center thereof; and two planar second die pads4, 6, each made of electric conductive material, disposed on both sidesof the first die pad 2. The three die pads 2, 4, 6 are included in thesame plane and are arranged along a single line. One main surface of thelead frame 1 includes the mounting surface of the first die pad 2 andthe mounting surfaces of the second die pads 4, 6. A plurality ofoptical devices are mounted on the mounting surface of the first die pad2, whereas semiconductor circuit devices (hereinafter referred to ascircuit devices) 30, 32 are mounted on the mounting surfaces of thesecond die pads 4, 6. The circuit devices 30, 32 are electricallyconnected to the optical devices, thereby processing electric signalsassociated with the optical devices. Here, each of the first die pad 2and the second die pads 4, 6 has substantially a rectangular or squareform.

Mounted on the first die pad 2 are a plurality of optical devices, eachof which is one of a semiconductor light-receiving device (hereinafterreferred to as light-receiving device) and a semiconductorlight-emitting device (hereinafter referred to as light-emittingdevice). The light-receiving device can receive an optical signal,converts thus received optical signal to an electric signal, and outputsthus obtained electric signal. The light-emitting device receives anelectric signal, converts thus received electric signal to an opticalsignal, and emits thus obtained optical signal.

FIG. 2 is a perspective view of a light-receiving device 20 and alight-emitting device 22 mounted on a die capacitor 10. In FIG. 2, thelight-receiving device 22 is mounted on an electrode 14 formed on theupper face of the die capacitor 10 shaped like a rectangularparallelepiped form, whereas the light-emitting device 22 is mounted onan electrode 16 formed on the upper face of the die capacitor 10. Thedie capacitor 10 mounted with the light-receiving device 20 and thelight-emitting device 22 is mounted on the first die pad 2 with itsrear-side electrode 18 faced to the mounting surface. As a consequence,the light-receiving device 20 and the light-emitting device 22 can beelectrically separated from the first die pad 2. Also, thelight-receiving device 20 and the light-emitting device 22 are mountedsuch that both of their optical axes 24, 26 become substantiallyperpendicular to the mounting surface of the die capacitor 10.

The electric power to the light-receiving device 20 and the electricpower to light-emitting device 22 are supplied by way of the respectiveelectrodes 14, 16 formed with these devices. For example, the power tothe light-receiving device 20 is supplied by an electrode pad formed onthe surface thereof and connected to the electrode 14 via a wire,whereas the electric power to the light-emitting device 22 is suppliedfrom the rear side of the light-emitting device. After the devices 20,22 are mounted, the respective electrode pads on the devices, the firstdie pad, and their corresponding connection leads 44 are connected toeach other by bonding wires.

In the example shown in FIG. 2, the light-receiving device 20 can be asurface receiving type light-receiving device, whereby it receivessignal light arriving at the receiving surface side of thelight-receiving device 20, e.g., the signal light arriving along thearrow 24. The surface receiving type light-receiving device includes aphotodiode. Also, the light-emitting device 22 can be a surface emissiontype light-emitting device, whereby the light-emitting device 22 emitssignal light from the surface, for example, along the direction of thearrow 26. The surface emission type light-emitting device includes alight-emitting diode.

In place of the die capacitor 10, a sub-mount 12 can be used. FIG. 3 isa perspective view of a sub-mount. As shown in FIG. 3, the sub-mount 12shaped like a rectangular parallelepiped form can be mounted on thefirst die pad 2, and the light-emitting devices 28 can be mountedthereon with their rear faces facing one side of the sub-mount 12. Also,the light-emitting devices 28 can be mounted on a side of the sub-mount12 with their rear faces directed to the side, and the sub-mount 12mounted with the light-emitting devices 28 can further be mounted on thefirst die pad 2. The light-emitting devices 28 are mounted such thattheir optical axes 34 extend parallel along the mounting side of thesub-mount 12. In the example as shown in FIG. 3, each of thelight-emitting devices 28 is an edge emission type light-emittingdevice, whereby they are preferably mounted such that their respectiveoptical axes 34 are parallel to each other and substantiallyperpendicular to the mounting surface of the die pad 2. As aconsequence, a plurality of light-emitting devices 28 with optical axesaligned to each other can be provided. For example, the edge emissiontype device includes a semiconductor laser.

In the examples of FIGS. 2 and 3 mentioned above, the light-receivingdevice 20 and the light-emitting devices 22, 28 having substantially arectangular or square planar form are employed. Although explained arethe case where one light-receiving device 20 and one light-emittingdevice 22 are mounted and the case where two light-emitting devices 28are mounted, the present invention encompasses any combination of eachor a plurality of these optical devices (light-receiving device andlight-emitting device). For example, a plurality of light-receivingdevices can be mounted. The following explanations will be concernedwith a case where one light-receiving device 20 and one light-emittingdevice 22 are mounted on the first die pad.

In FIG. 1, the circuit devices 30, 32 are mounted on the mountingsurfaces of the second die pads 4, 6 with their rear faces faced to therespective mounting surfaces. The second die pad 4 is mounted with thecircuit device 30 and the like associated with the light-receivingdevice 20 mounted on the first die pad 2. Such a circuit device includesa main amplifier, a data recovery circuit, a clock extraction circuit, abypass capacitor, a coupling capacitor, and the like. These devices arearranged at their predetermined positions and are electrically connectedto the die pad 4 and inner leads 52 and among these individual devicesby bonding wires (not illustrated). The second die pad 6 is mounted withthe circuit device 32 and the like associated with the light-emittingdevice 22 mounted on the first die pad 2. Such a circuit device includesa light-emitting device driving circuit, a bypass capacitor, asemi-fixed resistor for adjusting bias current, and the like. Thesedevices are arranged at their predetermined positions and areelectrically connected to the die pad 6 and the inner leads 52 and amongthe individual devices by bonding wires (not illustrated).

Referring to FIG. 1, in addition to the first and second die pads 2, 4,6, the lead frame 1 has two group of connection leads 40, 42 and wiringleads 54, 56, 58. The first group of connection leads 40 is arrangedsuch that one end thereof faces one side of the substantiallyrectangular first die pad 2 (on the upper side of the first die pad 2 inthe drawing), and the other end thereof faces one side of the second diepad 4 (on the lower side of the second die pad 4 in the drawing). Thesecond group of connection leads 42 is arranged such that one endthereof faces one side of the substantially rectangular first die pad 2(on the lower side of the first die pad 2 in the drawing), and the otherend thereof faces one side of the second die pad 6 (on the upper side ofthe second die pad 6 in the drawing). The first and second connectionlead groups 40, 42 have a plurality of conductive connection leads 44,48 for electrically connecting the optical devices mounted on the firstdie pad 2 to the circuit devices mounted on the second die pads 4, 6,and are provided in the planes containing the first die pad 2 and thecorresponding second die pads 4, 6. Since the connection lead groups 40,42 are provided so as to connect the second die pads 4, 6 to the firstdie pad 2, the number of the groups is identical to that of the seconddie pads 4, 6.

The second die pads 4, 6 are arranged such that the first die pad 2 issandwiched therebetween, and the first die pad 2 and the second die pads4, 6 are arranged along a single line. The connection lead groups 40, 42are disposed so as to face a pair of opposed sides of the first die pad2, respectively, whereas the second die pads 4, 6 face the respectivesurfaces including the two sides of the first die pad 2. The connectionleads in the groups 40, 42 linearly extend from a pair of opposed sidesof the first die pad 2 perpendicularly to these sides (in verticaldirections in the drawing), respectively, so as to reach the respectivesides of the second die pads 4, 6. The connection lead groups 40, 42 canlinearly extend from a pair of opposed sides of the first die pad 2,respectively, while forming a predetermined angle with theircorresponding sides, so as to reach the respective side faces of thesecond die pads 4, 6.

As shown in FIG. 1, the connection leads 44 are disposed so as to befaced to their corresponding die pads, and are connected, by bondingwires (not illustrated), to the devices mounted on the die pads, or tothe wiring leads.

The connection leads 44, 48, provided so as to connect the first die pad2 mounted with the light-receiving device 20 to the second die pad 4mounted with the circuit device to be connected to the light-receivingdevice 20, include at least three lines consisting of a preamplifieroutput line, a preamplifier power line, and a ground line. If thepreamplifier power supply is to be separated from the power supply forthe light-receiving device 20, then four lines are necessary. FIG. 1shows a lead frame with four lines. The connection lead group 40consists of four connection leads in which three connection leads 44 areallocated to the preamplifier output line, preamplifier power line, andlight-receiving device power line, respectively, and one grounding lineis added thereto.

The first die pad 2 can be mounted with a preamplifier (not illustrated)which is provide so as to effect a current/voltage conversion of anelectric signal from the light-receiving device 20 and amplifying theresulting signal. In this case, it is preferred that the semiconductordevice including the preamplifier is directly mounted on the mountingsurface of the first die pad 2 with its rear face faced to the mountingsurface. The electrode pad on the semiconductor device, the die pad 2,and their corresponding connection leads 44 are electrically connectedto each other by bonding wires (not illustrated).

The connection leads 44, 48, provided so as to connect the first die pad2 mounted with the light-emitting device 22 to the second die pad 6mounted with the circuit device to be connected to the light-emittingdevice 22, include at least two lines consisting of a light-emittingdevice power line and a signal line. FIG. 1 shows a lead frame withthree lines. Namely, the connection lead group 42 consists of threeleads in which two connection leads 44 are allocated to thelight-emitting device power line and signal line, and one grounding lineis added thereto.

Together with the light-emitting device 22, its driving circuit devicecan be mounted on the first die pad 2. This configuration is determinedwhile considering both the influence on heat generation of the drivingcircuit and the noise reduction effect achieved when the driving circuitand the light-emitting device 22 are placed close to each other. If thedriving circuit device is mounted on the first die pad 2, it will benecessary to increase the number of connection leads as required.

The number of connection leads 44 would vary depending on the devicemounted on each die pad.

In FIG. 1, four leads composed of the wiring leads 54, 56, 58 arearranged at each of two sides of respective second die pad 4, 6. Thesecond pads 4, 6 are provided with a reference axis 8 verticallyextending through both the sides of the second die pads facing theircorresponding connection lead groups and the opposite sides pairedtherewith. The wiring leads 54, 56, 58 are arranged on both left andright sides of the reference axis 8 and are oriented outward withrespect to the reference axis 8. Each of the wiring leads 54, 56, 58 canbe composed of an inner lead portion 52 and an outer lead portion 50,51. Some of the inner leads 52 are arranged so as to face sides of thesecond die pads 4, 6 and are connected with the outer leads 50, 51, andothers are arranged so as to be connected with the connection leads 44,48. The outer leads 50, 51 are directed perpendicularly to both sides ofthe reference axis 8. They are arranged in so-called DIP. In the outerleads 50, 51, the outer leads 50 associated with the second die pad 4are shorter than the outer leads 51 associated therewith the second diepad 6.

The wiring leads 54 are signal lines and power lines for the circuitdevices mounted on the second die pads 4, 6, the wiring leads 56 are thegrounding lines, and the wiring leads 58 are signal lines and powerlines for the optical devices mounted on the first die pad 2.

The light-receiving device 20 and the light-emitting device 22 arecoupled to the circuit devices and the like via wiring leads by way ofthe connection leads 44, 48, or finally electrically coupled to theouter leads 50, 51 by way of the connection leads 44, 48.

FIGS. 4A and 5A are perspective views each showing an optical modulewhen the light-receiving device 20, light-emitting device 22, circuitdevice, and the like are mounted on their corresponding die pads 2, 4, 6and are encapsulated with resin. FIG. 4B is a vertical sectional viewtaken along the section I-I' indicated in FIG. 4A, whereas FIG. 5B is avertical sectional view taken along the section II-II' indicated in FIG.5A. In FIGS. 4B and 5B, the outer leads 50, 51 in each cross section arealso illustrated in order to clarify the positional relationship betweenthe die pads 4, 6 and the outer leads 50, 51.

Referring to FIGS. 4A and 5A, the first die pad 2, light-receivingdevice 20, and light-emitting device 22 are integrally encapsulated withan encapsulating resin body 66. As a consequence, an optical module withthe optical device resin-encapsulated therein can be provided. Resinemployed for the encapsulating resin body 66 is transparent to thewavelength of signal light associated the light-receiving device 20 andlight-emitting device 22. Also, on the optical axis 70 of signal lightassociated with the light-receiving device 20 and light-emitting device22, a light-collecting means 68 for signal light, e.g., condenser lens,is formed by the form of the encapsulating resin body 66. As aconsequence, it is not necessary to provide an external light-collectingmeans, and it is possible to provide an optical module including theoptical devices and the light-collecting means arranged on the commonoptical axis. Examples of the form of the light-collecting means includea convex form (the form of one surface of a convex lens) directedoutward on the encapsulating resin body 66. A plurality of opticaldevices, e.g., two optical devices consisting o f the e light-receivingd device 20 and the light-emitting device 22, can be provided with theirindividual condenser lenses or a single condenser lens. Such a condenserlens 68 can be formed when a molding die shaped into a predeterminedinner form is filled with resin. Here, for the alignment of the opticalaxis with a waveguide, it is preferred that the interval o f the opticalaxes of a plurality of optical devices be set to the e firament intervalof a two-firament connector, Multi-MT connector, LC connector and thelike, or the core interval of optical fibers in ribbon fiber cable.Since the core interval of the two-core LC connector is, for example,6.35 mm, and the light-emitting device and the light-receiving devicecan be packaged without difficulty when the present invention is appliedthereto.

Referring to FIG. 4A, the second die pads 4, 6 and the circuit devicesand the like are integrally molded with an encapsulating resin body 60shaped like a rectangular parallelepiped form. When circuit deviceportions are integrally encapsulated, then a smaller optical module insize can be provided. Referring to FIG. 5A, the second die pad 4 and thecircuit device 30 and the like mounted thereon are molded with a singleencapsulating resin body 62 shaped like a rectangular parallelepipedform, whereas the second die pad 6 and the circuit device 32 and thelike mounted thereon are molded with a different single encapsulatingresin body 64. When circuit device portions are separately encapsulated,then the flexibility for arranging the circuit device portion in thelight-emitting module can be enhanced. While thus encapsulated twosemiconductor device are completely overlaid on each other with apredetermined distance therebetween in the vertical direction in FIG.5A, there are cases where they do not or partly overlap each otherdepending on angles formed between the side face of the first die pad 2facing the connection lead group 40, 42 and the extending direction ofthe connection lead group 40, 42. The predetermined distance isdetermined by the distance between the connection lead groups 40, 42 forconnection with the optical device portions, i.e., the bent partposition of the connection lead portions. The encapsulating resin thatis not transparent to the signal light of the optical devices ispreferably used. In this case, noise light is prevented from reachingthe circuit devices mounted on the second die pads 4, 6 and therebycausing them to malfunction.

The lead frame 1 shown in FIGS. 4A and 4B and FIGS. 5A and 5B has a bentportion bent substantially at the right angle at a position near eachside of the first die pad 2, whereby the rear faces opposite to themounting surfaces of the second die pads 4, 6 are oriented inward withrespect to each other. Namely, the rear faces of the second die pads 4,6 face each other (FIGS. 4B, 5B). The connection lead group 40 and thesecond die pad 4 are included in one plane. The connection lead group 42and the second die pad 6 are included in another plane. These planes aresubstantially parallel to each other, while each of them is orthogonalto the plane including the mounting surface of the first die pad 2.

Therefore, in order for the optical module to have the configurationshown in FIG. 4A, it is necessary that the lead frame 1 be processedinto a predetermined form before encapsulation. In order for the opticalmodule to have a form shown in FIG. 5A, the lead frame 1 can be shapedeither before or after encapsulation.

The encapsulating resin bodies 60, 62, 64 can be formed together withthe encapsulating resin body 66. In this manner, the number ofencapsulating steps can be reduced. Here, the encapsulating resinsuitable for the optical devices should be used.

In the outer leads 50, 51, the outer leads 50 associated with the seconddie pad 4 are shorter than the outer leads 51 associated with the seconddie pad 6. If the position of the bent part of the shorter outer leadsis located outside the position of the bent part of the longer outerleads, then the ends of the shorter outer leads are placed on the innerside, and the ends of the longer outer leads are placed on the outerside, so that the lead ends align in two rows on each side. Therefore,even when the outer leads 50 and 51 are bent in the same direction afterencapsulation, the outer leads arranged in the same side would not comeinto contact with each other. The outer lead end positions substantiallyare also aligned with each other. Thus, the alignment makes it easy forthe optical module to be mounted onto a printed circuit board or thelike.

As explained in the foregoing, the optical module shown in FIG. 4A isconfigured such that, when a first plane is defined as a plaincontaining the mounting surface of the first die pad 2 mounted with aplurality of optical devices, a second plane is also defined as a plaincontaining the mounting surface of the second die pad 4 mounted with acircuit device electrically connected to at least one optical device,and a third plane is defined as a plain containing the mounting surfaceof the third die pad 6 mounted with a circuit device electricallyconnected to at least one optical device, then in terms of therelationship among the first, second, and third plains, the second planeand the third plane are substantially parallel to each other, the secondand third planes are substantially orthogonal to the first plane, andthe rear face of the second die pad 4 and the rear face of the seconddie pad 6 face each other. The first die pad 2 and the optical devicesare encapsulated with the encapsulating resin body 66, whereas thesecond die pads 4, 6 and the circuit devices 30 and 32 are encapsulatedwith the encapsulating resin body 60. The connection lead groups 40, 42extend from the encapsulating resin body 66 while being contained withinthe first plane. The groups 40, 42 are bend substantially at the rightangle at the respective positions where the groups 40, 42 intersect thesecond and third planes, so that the second and third planes can containthe groups 40, 42, respectively, and reach one side of the encapsulatingresin body 60 so as to be connected with the inner leads. The outerleads 50, 51 are contained within the second and third planes,respectively, extend both leftward and rightward orthogonal to theextending directions of the connection lead groups 40, 42, and then bendsubstantially at the right angle, all in the same direction, at theirrespective predetermined positions near their corresponding sides of theencapsulating resin body 60. The optical module shown in FIG. 5A has aconfiguration similar to that of FIG. 4A except that the second die pad4 and the circuit device 30 are molded with the encapsulating resin body62 and the second die pad 6 and the circuit device 32 are molded withthe encapsulating resin body 64.

FIG. 6A is a sectional view of the encapsulating resin body 66 (FIGS. 4Aand 4B and FIGS. 5A and 5B), and shows a cross section including thelight-collecting means 68 as well as the light-receiving device 20 andthe light-emitting device 22. The optical module is optically connectedwith an optical waveguide, e.g., a ribbon fiber cable 72. FIG. 6C showsa cross section of such a fiber cable 72. In the example of FIG. 6C, theribbon fiber cable 72 is configured such that two optical fibers 74 aredisposed along a reference axis with a predetermined core interval d,whereas the peripheries of the ribbon fibers 72 are coated with a resinbody 76.

In FIG. 6A, the ribbon fiber cable 72 is disposed on the optical axis ofthe light-collecting means 68. The respective optical axes of thelight-receiving device 20 and light-emitting device 22 are provided withthe distance d therebetween. The light 80 emitted from the optical fiber72 is collected by the light-collecting means 68 onto the surface of thelight-receiving device 20, whereby the receiving surface of thelight-receiving device 20 receives thus collected light 82. The light 84emitted from the emitting surface of light-emitting device 22 iscollected by the light-collecting means 68, and thus collected light 86is guided to the optical fiber. The respective optical axes of thelight-receiving device 20 and light-emitting device 22 can be arrangedwith the distance d behined the light-collecting means 68.

In FIG. 6B, each device is provided with one light-collecting means,i.e., a light-collecting means 69 is provided for the light-receivingdevice 20, and a light-collecting means 71 is provided for thelight-emitting device 22. In this example, the distance between therespective optical axes of the light-collecting means 69, 71 is d, whichcoincides with the core interval of the ribbon fiber cable 72. Thisconfiguration will not be explained further because it is the same asthat of FIG. 6A except that the respective light beams are collected bytheir corresponding light-collecting means 69, 71.

As explained in detail with reference to specific examples in theforegoing, a plurality of optical devices 20, 22 are mounted on the samemounting surface of the single first die pad 2, whereby the interval dof the optical devices can be reduced, and the receiving surface and theemitting surface thereof for the optical signal are faced to onedirection.

Since the lead frame 1 carrying the optical devices are also providedwith a plurality of second die pads 4, 6, which are mounted with theirrespective circuit devices 30, 32, a mounting area required for aplurality of circuit devices electrically connected to the opticaldevices can be secured.

Further, by means of the connection lead groups 40, 42, the opticaldevices 20, 22 mounted on the first die pad 2 can be directly andelectrically connected, within the lead frame, to the circuit devices30, 32 mounted on the second die pads. The number of the groups 40, 42is identical to the number of the second die pads 4, 6. Each of thegroups 40, 42 comprises a plurality of connection leads 44, 48. Eachconnection lead group has one end disposed so as to face one side faceof the first die pad 2 and the other end disposed so as to face one sideface of the second die pad 4, 6. Consequently, the number of wiringleads can be reduced.

In addition, the connection lead groups 40, 42 are bent at theirrespective bent parts located at their predetermined positions, so thatthe rear faces opposite to the mounting surfaces of the two second diepads 4, 6 are oriented inward with respect to each other, whereby thetwo-dimensional size of the optical module can be reduced. Namely, themounting density of the light-receiving device, light-emitting device,circuit devices, and the like can be enhanced.

(Second Embodiment)

FIG. 7 is a plan view of a major portion of the optical module leadframe in accordance with the second embodiment. Referring to FIG. 7,this lead frame 101 has a basic configuration similar to that of thefirst embodiment. Namely, the lead frame 101 comprises a planar firstdie pad 102, made of a electric conductive material, located at thecenter thereof; and two planar second die pads 104, 106, each made of aconductive material, disposed on both sides of the first die pad 102.The three die pads 102, 104, 106 are contained within the same plane andare arranged on a single line. The mounting surface of the first die pad102 and the mounting surfaces of the second die pads 104, 106 coincidewith one main surf ace of the lead frame 1. Further, the lead frame 101has connection lead groups 140, 142, and wiring leads 154, 156, 158. Thefirst and second connection lead groups 140, 142 have a plurality ofconducting connection leads 144, 148, provided for electricallyconnecting the optical devices mounted on the first die pad, to thecircuit devices mounted on the second die pads, and are included withinthe same plane as the first die pad 102 and second die pads 104, 106.

The lead frame 101 shown in FIG. 7 will not be explained in detailbecause it has substantially the same configuration as that of the leadframe 1 in the first embodiment except for the configuration concerningthe directions in which the wiring leads 154, 156, 158 are drawn.Individual parts of the lead frame 101 in FIG. 7 are referred to withreference numbers produced by adding one hundred to the numbersindicating their corresponding parts of the lead frame 1 of FIG. 1,except for the reference numbers for the optical devices 10 and thecircuit devices 30, 32 and the like.

Although a plurality of optical devices 10 and the like are mounted onthe mounting surface of the first die pad 102, and the circuit devices30, 32 electrically connected to the optical devices and the like arealso mounted on the mounting surfaces of the second die pads 104, 106,respectively, as with the first embodiment, the configuration is notlimited thereto.

Referring to FIG. 7, eight leads composed of the wiring leads 154, 156,158 are arranged in one side of each of the second die pads 104, 106.The second pads 104, 106 are provided with a reference axis 108extending vertically through both the side of each second die pad facingits corresponding connection lead group 140, 142 and its opposite sidepaired therewith. In the second die pad 104, the wiring leads 154, 156,158 are arranged on one of the left and right sides (left side in FIG.7) of the reference axis 108 provided in the second die pad 104. In thesecond pad 106, the wiring leads 154, 156, 158 are arranged on one ofthe left and right sides (right side in FIG. 7) of the reference axis108 provided in the second die pad 106. In each second die pad 104, 106,the wiring leads 154, 156, 158 are oriented outward with respect to thereference axis 108. As with the first embodiment, each of the wiringleads 154, 156, 158 has an inner lead portion 152 and an outer leadportion 150, 151. The outer leads 150, 151 are directed, outward, toboth sides perpendicular to the reference axis 108. In the outer leads,the outer leads 150 associated with the second die pad 104 are shorterthan the outer leads 151 associated with the second die pad 106.

FIGS. 8A and 9A are perspective views of optical modules after thelight-receiving device 20, light-emitting device 22, circuit devices 30,34, and the like are mounted on their corresponding die pads 102, 104,106 and are encapsulated with resin. Referring to FIGS. 8A and 9A, aswith the first embodiment, an optical module in which the first die pad102, light-receiving device 20, and light-emitting device 22 are moldedwith a single encapsulating resin body 166 is provided. On the opticalaxis 170 of signal light associated with the light-receiving device 20and light-emitting device 22, light-collecting means 168, 169 for signallight such as condenser lens are provided by the form of theencapsulating resin body 166. As a consequence, it is not necessary toprovide separated light-collecting means, and it is possible to providean optical module in which the optical devices and the light-collectingmeans are arranged on the common optical axis. The encapsulating resin,the shape of the light-collecting means 68, and the like are notexplained in detail because they are similar to those of the firstembodiment.

Referring to FIG. 8A, as with the first embodiment, the second pads 104,106, the circuit devices 30, 32 and the like are molded with a singleencapsulating resin body 160 shaped like a rectangular parallelepipedform. Referring to FIG. 9A, as with the first embodiment, the second diepad 104 and the circuit device 30 and the like mounted thereon areencapsulated with a single encapsulating resin body 162 shaped like arectangular parallelepiped form, whereas the second die pad 106 and thecircuit device 32 mounted thereon and the like are molded with adifferent single encapsulating resin body 164. While thus encapsulatedtwo semiconductor devices are completely overlaid on each other with apredetermined distance therebetween in the vertical direction of FIG.9A, they do not or partly overlap each other depending on an angleformed between the side of the first die pad 102 facing the connectionlead groups 140, 142 and the direction in which the connection leadgroups 140, 142 extend. The predetermined distance is determined by thedistance between the connection lead groups 140, 142 for connection withthe optical device portions.

As with the first embodiment, in the lead frame 101 shown in FIGS. 8Aand 8B and FIGS. 9A and 9B, the connection lead groups 140, 142 are bentsubstantially at the right angle at their respective positions neartheir corresponding sides of the first die pad 102, whereby the rearfaces of the second die pads 104, 106 are oriented inward. As aconsequence, the connection lead group 140 and the second die pad 104are contained within one plane, the connection lead group 142 and thesecond die pad 106 are contained within the other plane, and theseplanes are substantially parallel to each other, while each of them isorthogonal to the plane including the mounting surface of the first diepad 102.

FIG. 8B is a vertical sectional view taken along the section III-III'indicated in FIG. 9A, whereas FIG. 9B is a vertical sectional view takenalong the section IV-IV' indicated in FIG. 9A. In FIGS. 8B and 9B, theouter leads 150, 151 in each cross section are illustrated in order toclarify the positional relationship between the die pads 104, 106 andthe outer leads 150, 151.

In the outer leads 150, 151, since the outer leads 150 associated withthe second die pad 104 are shorter than the outer leads 151 associatedwith the second die pad 106. When the outer leads 150 and 151 are bentin the same direction after encapsulation, the outer leads arranged onthe same side of the molded body would not come into contact with eachother, and the outer lead end positions substantially align with eachother. Since the outer leads 150, 151 are disposed at two opposed sides,respectively, the bent parts of the shorter outer leads and the longerouter leads can be placed at substantially the same position. As aconsequence, it becomes easier to bend the outer leads in each side.When the outer leads 150 and 151 are bent in the same direction afterencapsulation, the lead ends are aligned in one row on each side face,and the outer lead end positions are substantially aligned with eachother. The alignment makes it easy for the optical module to be mountedonto a printed circuit board or the like.

As explained in the foregoing, the optical module shown in FIG. 8A isconfigured such that, when a first plane is defined as a plaincontaining the mounting surface of the first die pad 102 mounting aplurality of optical devices, a second plane is defined as a plaincontaining the mounting surface of the second die pad 104 mounting acircuit device electrically connected to at least one optical device,and a third plane is defined as a plain containing the mounting surfaceof the third die pad 106 mounting a circuit device electricallyconnected to at least one optical device, then the three plains have therelationship as follows: the second plane and the third plane aresubstantially parallel to each other; the second and third planes aresubstantially orthogonal to the first plane; and the rear face oppositeto the mounting surface of the second die pad 104 faces the rear faceopposite to the mounting surface of the second die pad 106. The firstdie pad 102 and the optical devices are encapsulated with theencapsulating resin body 166, whereas the second die pads 104, 106 andthe light-emitting device and light-receiving device 20, 22 are moldedwith the encapsulating resin body 160. The connection lead groups 140,142 extend from the encapsulating resin body 166 while being containedwithin the first plane. The connection lead groups 140, 142 are bendsubstantially at the right angle at the respective positions at whichthe groups 140, 142 intersect the second and third planes, so that thegroups 140, 142 are contained within the second and third planes,respectively, and reach one side of the encapsulating resin body 160 soas to be connected with the inner leads. The outer leads 150 arecontained within the third plane and extend to one of the leftward andrightward directions (leftward in FIG. 8A) orthogonal to the directionin which the connection lead groups 140, 142 extend. The outer leads 151are contained within the second plane and extend to one of the leftwardand rightward directions (rightward in FIG. 8A) orthogonal to thedirection in which the connection lead groups 140, 142 extend. The outerleads 150, 151 are bent substantially at the right angle, all in thesame direction, at their respective predetermined position near theircorresponding sides of the encapsulating resin body 160. The opticalmodule shown in FIG. 9A has a configuration similar to that of FIG. 8Aexcept that the second die pad 104 and the circuit device 30 areencapsulated with the encapsulating resin body 162, and that the seconddie pad 106 and the circuit device 32 are encapsulated with theencapsulating resin body 164.

Thus, as with the first embodiment, the distance d of the opticaldevices can be reduced, the direction of the emitting surfaces for theoptical signal coincides with that of the receiving surface, and amounting area required for a plurality of circuit devices can besecured. The connection lead groups 140, 142, the number of which isidentical to that of the second die pads 104, 106, are provided, andeach connection group has a plurality of connection leads 144, 148,whereby the number of wiring leads can be reduced. In addition, sincethe connection lead groups 140, 142 are bent substantially at the rightangle at their predetermined positions, so that the rear faces oppositeto the mounting surfaces of the two second die pads 104, 106 areoriented inward with respect to each other. The optical module can bereduced in the two-dimensional size, whereby the mounting density of thedevices can be enhanced.

(Third Embodiment)

FIG. 10 is a plan view of a major portion of the optical module leadframe 201 in accordance with the embodiment. The lead frame 201 shown inFIG. 10 will not be explained in detail because it has substantially thesame configuration as that of the lead frame 101 in the secondembodiment except for the configuration concerning the directions inwhich wiring leads 254, 256, 258 are drawn. Individual parts of the leadframe 101 in the second embodiment and their corresponding parts of thelead frame 201 in the third embodiment are referred to with referencenumerals whose lower two digits are common in FIGS. 7 and 10, except forthe optical devices 10 and the circuit devices 30, 32, and the like.

FIGS. 11A and 12A are perspective views of optical module in which thelight-receiving device 20, light-emitting device 22, circuit devices 30,32, and the like are mounted on their corresponding die pads 202, 204,206 and encapsulated with resin. Referring to FIGS. 11A and 12A, as withthe second embodiment, an optical module in which the first die pad 202,light-receiving device 20, and light-emitting device 22 are integrallyencapsulated with an encapsulating resin body 266 is provided. Unlikethe first and second embodiments, depicted are the optical module havingthe flat surface of the resin body on the optical axis 270 of signallight associated with the light-receiving device 20 and light-emittingdevice 22 without specific light-collecting means for signal light. Theencapsulating resin and the like are not explained in detail becausethey are similar to those of the second embodiment.

Referring to FIG. 11A, as with the second embodiment, the second pads204, 206 and the circuit devices 30, 32 and the like are encapsulatedwith a single encapsulating resin body 260 shaped in a rectangularparallelepiped form. Referring to FIG. 12A, as with the secondembodiment, the second die pad 204 and the circuit device 30 mountedthereon or the like are encapsulated with a single encapsulating resinbody 262 shaped in a rectangular parallelepiped form, whereas the seconddie pad 206 and the circuit device 32 or the like mounted thereon areencapsulated with a different single encapsulating resin body 264. Thusencapsulated two semiconductor devices are arranged so as to bevertically overlaid on each other with a predetermined distancetherebetween.

As with the above-mentioned embodiments, in the lead frame 201 shown inFIGS. 11A and 11B and FIGS. 12A and 12B, the connection lead groups 240,242 are bent substantially at right angles at their respective positionsnear their corresponding side faces of the first die pad 202, wherebythe rear faces opposite to the mounting surfaces of the second die pads204, 206 are oriented inward with respect to each other. As aconsequence, the connection lead group 240 and the second die pad 204are contained within one plane, the connection lead group 242 and thesecond die pad 206 are also contained within the other plane. Theseplanes are substantially parallel to each other, while each of them isorthogonal to the plane containing the mounting surface of the first diepad 202.

FIG. 11B is a vertical sectional view taken along the section V-V'indicated in FIG. 11A, whereas FIG. 12B is a vertical sectional viewtaken along the section VI-VI' indicated in FIG. 12A. FIGS. 11B and 12Billustrate the outer leads 250, 251 in each cross section in order toclarify the positional relationship between the die pads 204, 206 andthe outer leads 250, 251.

In the outer leads 250, 251, the outer leads 250 associated with thesecond die pad 204 are shorter than the outer leads 251 associated withthe second die pad 206. If the position of the bent parts of the shorterouter leads is located inside the position of the bent parts of thelonger outer leads, then the ends of the shorter outer leads are placedon the inner side, and the ends of the longer outer leads are placed onthe outer side, so that these lead ends are aligned in two rows on eachside. Therefore, even when the outer leads 250 and 251 are bent in thesame direction after encapsulation, the outer leads disposed in the sameside face would not come into contact with each other, and the outerlead end positions substantially are aligned with each other, Thealignment allows the easy mounting of the optical module on a printedcircuit board or the like.

As explained in the foregoing, the optical module shown in FIG. 11A hasa configuration in terms of the relationship among a first plane, asecond plane, and a third plane as described below: the first planeincludes the mounting surface of the first die pad 202 mounting aplurality of optical devices; a second plane includes the mountingsurface of the second die pad 204 mounting a circuit device electricallyconnected to at least one optical device; and a third plane includes themounting surface of the third die pad 206 mounting a circuit deviceelectrically connected to at least one optical device. The configurationis described below: the second plane and the third plane aresubstantially parallel to each other; and the second and third planesare substantially orthogonal to the first plane. The rear face oppositeto the mounting surface of the second die pad 204 faces that of thesecond die pad 206. The first die pad 102 and the optical devices areencapsulated with the encapsulating resin body 266, whereas the seconddie pads 204, 206, the light-receiving device 20 and the light-emittingdevices 22 are encapsulated with the encapsulating resin body 260. Theconnection lead groups 240, 242 extend from the encapsulating resin body266 while being contained within the first plane. The groups 140, 142bend substantially at the right angle at the respective positions atwhich the groups 140, 142 intersect the second and third planes,respectively, so as to be contained within the second and third planes,and reach one side of the encapsulating resin body 260 so as to beconnected with the inner leads. The outer leads 250 are contained withinthe third plane, whereas the outer leads 251 are contained within thesecond plane. The outer leads 250, 251 are arranged only at the rearface opposite to the side of the encapsulating resin body 260 faced tothe encapsulating resin body 266, and also extend in the directions inwhich the connection lead groups 240, 242 extend, respectively. Theouter leads 250, 251 are bent substantially at the right angle, all inone direction, at their respective predetermined position near theircorresponding side of the encapsulating resin body 260. The opticalmodule shown in FIG. 12A has a configuration similar to that of FIG. 11Aexcept that the second die pad 204 and the circuit device 30 are moldedwith the encapsulating resin body 262 and the second die pad 206 and thecircuit device 32 are encapsulated with the encapsulating resin body264.

Thus, as with the second embodiment, the interval d of the opticaldevices can be reduced, the direction of the emitting surface for theoptical signal coincide with that of the receiving surface, and amounting area required for a plurality of circuit devices 30, 32 can besecured. The number of the connection lead groups 240, 242 is identicalto that of the second die pads 204, 206, whereby the number of wiringleads can be reduced. Also, the connection lead groups 240, 242 are bentsubstantially at the right angle at their predetermined positions, sothat the rear faces of the two second die pads 204, 206 are orientedinward with respect to each other. The optical module can be reduced intwo-dimensional size, whereby the mounting density of the devices andthe like can be increased.

(Fourth Embodiment)

FIG. 13 is a plan view of a major portion of the optical module leadframe 301 in accordance with the fourth embodiment. The lead frame 301shown in FIG. 13 will not be explained in detail because it hassubstantially the same configuration as those of the lead frame 1 in thefirst embodiment except for directions in which wiring leads 354, 356,358 are drawn. Individual parts of the lead frame 301 in FIG. 13 arereferred to with reference numbers produced by adding three hundreds tothe numbers of their corresponding parts in the lead frame 1 in FIG. 1except for the optical devices 10, the circuit devices 30, 32 and thelike.

Referring to FIG. 13, the lead frame 301 has connection lead groups 340,342 and wiring leads 354, 356, 358 in addition to the first and seconddie pads 302, 304, 306. The first connection lead group 340 is providedsuch that one end thereof faces one side of the substantiallyrectangular first die pad 302 (on the upper side of the first die pad302 in the drawing), and the other end thereof faces one side of thesecond die pad 304 (on the lower side of the second die pad 304 in thedrawing.) The second connection lead group 342 is provided such that oneend thereof faces one side face of the substantially rectangular firstdie pad 302 (on the lower side of the first die pad 302 in the drawing),and the other end thereof faces one side face of the second die pad 306(on the upper side of the second die pad 306 in the drawing). The firstand second connection lead groups 340, 342 have a plurality ofconductive connection leads 344, 348 provided for electricallyconnecting the optical devices mounted on the first die pad 302 to thecircuit devices mounted on the second die pads 304, 306, and arearranged in the same plane as the first die pad 302 and the second diepads 304, 306.

The first die pad 302 is sandwiched between second die pads 304, 306,and the first die pad 302 and the second die pads 304, 306 are arrangedon a single line. The connection lead groups 340, 342 are arranged so asto face a pair of opposed sides of the first die pad 302, respectively,whereas the second die pads 304, 306 face the respective surfacesincluding the pair of sides. The connection lead groups 340, 342 extendalong a reference axis 300 extending vertically through the pair of theabove-mentioned two opposed sides, i.e., in a direction perpendicular toone side of the die pad 302 (the vertical direction in the drawing.) Theconnection lead group 340 bends at its first position toward one of theleft and right sides of the reference axis 300 at a predetermined angle,whereas the connection lead group 342 bends at its first position towardthe other of the left and right sides of the reference axis 300 at thesame angle. The connection lead groups 340, 342 bend at their respectivesecond positions, which are different from the first positions, so as toextend parallel to the reference axis 300 and reach their respectivesides of the second die pads 304, 306. The predetermined angle isgreater than 0 degrees but smaller than 90 degrees.

FIG. 14A is a top plan view of an optical module in which devices 10,20, 22 and the like are provided on the optical module lead frame 301shown in FIG. 13 and encapsulated with an encapsulating resin. FIG. 14Bis a bottom view thereof. FIG. 14C is a front view thereof. FIG. 14D isa sectional view taken along the section VII-VII' indicated in FIG. 14A.Here, FIG. 14D shows only the parts appearing in the cross section.

Referring to FIGS. 14A to 14C, as with the first embodiment, an opticalmodule in which the first die pad 302, the light-receiving device 20,and the light-emitting device 22 are integrally encapsulated with anencapsulating resin body 366 is provided. On the optical axis 370 ofsignal light associated with the light-receiving device 20 andlight-emitting device 22, a condenser lens for signal light is formed bythe form of the encapsulating resin body 366. The second die pad 304 andthe circuit device 30 or the like mounted thereon are molded with asingle encapsulating resin body 362 shaped in a rectangularparallelepiped form, whereas the second die pad 306 and the circuitdevice 32 mounted thereon or the like are molded with a different singleencapsulating resin body 364. Referring to FIG. 14D, two encapsulatedmembers 362, 364 are arranged without vertically overlapping each other.The respective heights of the members 362, 364 differ from each other bythe distance between the connection lead groups 340, 342 for connectionwith the optical device portion.

As with the first embodiment, the lead frame 301 as shown in FIGS. 14Ato 14D is bent substantially at the right angle at respective positionsnear the sides of the first die pad 302, while the rear faces oppositeto the mounting surfaces of the second die pads 304, 306 are facedinward. As a consequence, the connection lead group 340 and the seconddie pad 304 are contained within one plane, the connection lead group342 and the second die pad 306 are contained within the other plane, andthese planes are substantially parallel to each other, while each ofthem is orthogonal to the plane including the mounting surface of thefirst die pad 302.

FIGS. 14C and 14D also show the outer leads 350, 351 so as to clarifythe positional relationship between the die pads 304, 306 and the outerleads 350, 351.

As for the outer leads 350, 351, the outer leads 350 associated with thesecond die pad 304 are shorter than the outer leads 351 associated withthe second die pad 306, whereby the outer lead end positionssubstantially are aligned with each other when the outer leads 350, 351are bent substantially at the right angle in the same direction afterencapsulation.

Since the outer leads 350, 351 extend from the encapsulating resinbodies 362, 364 arranged in parallel, respectively, the bent part of theshorter outer leads and the bent part of the longer outer leads can beplaced substantially at the same position. As a consequence, when theouter leads 350 and 351 are bent in the same direction afterencapsulation, the lead ends in each side align in one row. Hence, theouter leads arranged on the same side can be bent easily, and the outerlead end positions substantially align with each other, whereby mountingonto a printed circuit board or the like becomes easier.

As explained in the foregoing, the optical module shown in FIGS. 14A to14D has a configuration in terms of the relationship among a firstplain, a second plain, and a third plain: the first plane includes themounting surface of the first die pad 302 mounting a plurality ofoptical devices; the second plane includes the mounting surface of thesecond die pad 304 mounting a circuit device electrically connected toat least one optical device; and the third plane includes the mountingsurface of the third die pad 306 mounting a circuit device electricallyconnected to at least one optical device. The configuration is asfollows: the second and third planes are substantially orthogonal to thefirst plan; the second plane and the third plane are substantiallyparallel to each other; and the rear face of the second die pad 304 andthe rear face of the second die pad 306 face inward with respect to eachother. The first die pad 302 and the optical devices are encapsulatedwith the encapsulating resin body 366. The second die pad 304 and thecircuit device 30 are encapsulated with the encapsulating resin body362. The second die pad 306 and the circuit device 32 are encapsulatedwith the encapsulating resin body 364. The connection lead groups 340,342 extend from the encapsulating resin body 366 while being included inthe first plane. The connection lead group 340 bends substantially atthe right angle at a position where the group 340 intersects the secondplane, extends while being contained in the second plane, reaches oneside of the encapsulating resin body 362, and connects with the innerleads 352. The connection lead group 342 bends substantially at theright angle at a position where the group 342 intersects the thirdplane, extends while being contained within the third plane, reaches oneside of the encapsulating resin body 364, and connects with the innerleads 352. The outer leads 350 are contained within the second plane,whereas the outer leads 351 are contained within the third plane. Theouter leads 350, 351 extend both leftward and rightward of therespective axes extending vertically through both the surfaces of theencapsulating resin bodies 362, 364 facing the encapsulating resin body366 and their opposed surfaces. These leads 350, 351 bend substantiallyat the right angle, all in one direction, at their predeterminedpositions near the corresponding sides of the encapsulating resin bodies362, 364.

Thus, as with the first embodiment, the interval d of the opticaldevices can be reduced, the emitting surface and receiving surfacethereof for the optical signal are allowed to face to the samedirection, and a mounting area required for a plurality of circuitdevices can be secured. The number of the connection lead groups 340,342 is identical to that of the second die pads 304, 306, each of thegroups 340, 342 has a plurality of connection leads 344, 348,whereby thenumber of wiring leads can be reduced. Also, since the connection leadgroups 340, 342 are bent substantially at the right angle at theirpredetermined positions, so that the rear faces of the two second diepads 304, 306 are oriented inward with respect to each other, thetwo-dimensional size of the optical module can be reduced, whereby themounting density of the devices and the like can be enhanced.

Industrial Applicability

As explained in detail in the foregoing, a plurality of optical devicesare provided on a single first die pad of the optical module inaccordance with the present invention, whereby the interval of theoptical devices can be reduced, and the direction of the emittingsurface for the optical signal can coincide with that of the receivingsurface. Also, the lead frame provided with the optical devicescomprises a plurality of second die pads, each of 51, which can bemounted with their circuit devices, whereby an area for mounting aplurality of circuit devices can be secured. Further, the number of theconnection lead groups is identical to that of the second die pads. Eachof the connection lead groups comprises a plurality of connection leads,each of which has one end provided so as to face one side of the firstdie pad and the other end provided so as to face one side of the seconddie. The connection lead groups allows the optical devices mounted onthe first die pad to be directly connected to the circuit devicesmounted on the second die pads. As a consequence, the number of wiringleads can be reduced. Hence, it is possible to provide an optical modulein which a plurality of optical devices are integrally mounted andmolded, whereby the mounting density of the devices and the like can beenhanced.

The optical module lead frame in accordance with the present inventionhas a single first die pad for mounting a plurality of optical devices,whereby it allows the optical devices to be arranged with the reducedinterval thereof, and also allows the emitting surface and the receivingsurface for the optical signal to face to the same direction. Also, thelead frame provided with the optical devices comprises a plurality ofsecond die pads provided for mounting the circuit devices correspondingto the respective optical devices, whereby a mounting area for aplurality of circuit devices can be secured. Further, the lead framecomprises the connection lead groups for directly electricallyconnecting the optical devices mounted on the first die pad to thecircuit devices mounted on the second die pads. The number of the groupsis identical to that of the second die pads. Each of the groupscomprises a plurality of connection lead. Each of the connection leadshas one end arranged so as to face one side of the first die pad and theother end arranged so as to face one side of the second die. Therefore,the number of wiring leads can be reduced.

Hence, it is possible to provide an optical module, having a pluralityof circuit devices, in which a plurality of optical devices can beintegrally mounted and molded, and a lead frame for the optical module.They are suitable for attaining the smaller size and the higher densitythereof.

What is claimed is:
 1. An optical module comprising:optical devicesincluding one of a semiconductor light-receiving device and asemiconductor light-emitting device, said semiconductor light-receivingdevice being provided so as to receive an optical signal, convert thusreceived optical signal into an electric signal, and output thusobtained electric signal, and said semiconductor light-emitting devicebeing provided so as to receive an electric signal, convert thusreceived electric signal into an optical signal, and emit thus obtainedoptical signal; semiconductor circuit devices, electrically coupled tosaid optical devices, provided so as to process said electric signal; alead frame mounting said optical devices and said semiconductor circuitdevice thereon; and a first encapsulating resin body, transparent tolight of the optical signal processed by said optical devices, providedso as to encapsulate said optical devices; wherein said lead frame has asingle first die pad provided so as to mount a plurality of said opticaldevices; a plurality of second die pads provided so as to mount aplurality of said semiconductor circuit devices respectively; connectionlead groups provided so as to electrically connect the optical devicemounted on said first die pad to said semiconductor circuit devicesmounted on said second die pads, the number of said connection leadgroups being identical to the number of said second die pads, saidconnection lead groups each having a plurality of connection leads, andsaid connection lead groups each having one end arranged so as to faceone side of said first die pad and the other end arranged so as to faceone side of said second die pad; and wiring leads arranged so as to facea side of said second die pads; and wherein said optical devices iselectrically connected to said wiring leads by way of said connectionleads.
 2. An optical module according to claim 1, wherein said leadframe has two said second die pads, said connection lead groups beingarranged so as to face a pair of two sides of said first die pad,respectively; said connection lead groups each having a bent portionbent substantially at the right angle at a predetermined positionthereof such that the respective rear faces opposite to the mountingsurfaces of said second die pads are oriented to face each other.
 3. Anoptical module according to claim 1, wherein said first encapsulatingresin has light-collecting means, said light-collecting means beingprovided on optical axes of the signal light associated with saidoptical devices.
 4. An optical module according to claim 2, furthercomprising a second encapsulating resin body provided so as tointegrally encapsulating said semiconductor circuit devices mounted onsaid respective second die pads.
 5. An optical module according to claim2, further comprising second encapsulating resin bodies provided so asto separately encapsulate said semiconductor circuit devices mounted onsaid respective second die pads.
 6. An optical module according to claim1, wherein said optical devices are arranged on said first die pad suchthat the optical axes of said optical devices is conformed to a coreinterval of adjacent optical fibers in a ribbon fiber cable.
 7. A leadframe for an optical lead frame provided so as to arrange opticaldevices and semiconductor circuit devices thereon, wherein the opticaldevices includes at least one of a semiconductor light-receiving devicefor receiving an optical signal, converting thus received optical signalinto an electric signal, and outputting thus obtained electric signal,and the semiconductor light-emitting device for receiving an electricsignal, converting thus received electric signal into an optical signal,and emitting thus obtained optical signal; and wherein the semiconductorcircuit devices for processing said electric signal being provided so asto be electrically connected to said optical devices; said lead framecomprising:a single first die pad provided so as to arrange said opticaldevices; a plurality of second die pads provided so as to arrange saidsemiconductor circuit devices; connection lead groups provided so as toelectrically connect the optical devices mounted on said first die padto the semiconductor circuit devices mounted on said second die pads,respectively, said connection lead groups each having a plurality ofconnection leads, said connection lead groups each having one endarranged so as to face one side of said first die pad and the other endarranged so as to face one side of said second die pad, and the numberof said connection lead groups being identical to the number of saidsecond die pads; and a plurality of wiring leads provided so as toelectrically connect said semiconductor circuit devices and said opticaldevices to outside, the plurality of wiring leads facing sides of saidsecond die pads.
 8. A lead frame according to claim 7, wherein saidsecond die pads are two, said connection lead groups each having a partto be bent substantially at the right angle, said connection lead groupsbeing arranged so as to face a pair of two sides of said first die pad,said second die pads facing respective faces including said pair of twosides of said first pad, said second die pads being arranged on a axiswith said first die pad sandwiched therebetween.
 9. A lead frameaccording to claim 8, wherein said second die pads have reference axesextending through both sides of the second die pads facing saidconnection lead groups and opposite sides paired therewith, said wiringleads being arranged so as to face the left and right sides of saidreference axes.
 10. A lead frame according to claim 8, wherein saidsecond die pads have reference axes extending through both sides of saidsecond die pads facing said connection lead groups and opposite sidespaired therewith, said wiring leads being arranged so as to face one ofthe left and right sides of the reference axis in one of said second diepads, said wiring leads is arranged so as to face the other of the leftand right sides of the reference axis in the other of said second diepads.
 11. A lead frame according to claim 8, wherein said wiring leadsare arranged so as to face sides of said second die pads, said sidesthereof being opposite to sides thereof on which said second die padsface said first die pad.